1. Field of the Invention
The present invention relates to an electrical connector for electrically connecting an exterior mating connector to a circuit board, and particularly to an electrical connector having an improved shell means for enhancing the retentive effect with both an insulative housing of the connector and the circuit board.
2. The Prior Art
Due to the trend of current market demand, some electrical connectors, like the mini type connector, are generally dimensioned to be increasingly smaller and more delicate. However, as the miniaturization of connector design progresses, some retentive structures provided by electrical connectors with regard to a shell of the housing are compromised diminishing the retentive effect therebetween. In addition, such a shell lacks a retentive structure to ensure direct and continuous retainment on the circuit board. Therefore, the shell of the connector may become loose after repeated engagements and disengagements with an exterior mating connector. Such electrical connectors can refer to the disclosures of U.S. Pat. Nos. 4,842,554 and 5,186,633.
Other electrical connectors are proposed that adopt surface mounting technology (SMT) to retain the shell of the connector onto a surface of the circuit board whereby the connector can engage the shell to be retentively mounted on said surface of the circuit board to enhance the retentive effect as mentioned above. If corresponding grounding circuits exist on said surface of the circuit board, the mounted shell can further provide the connector with grounding capability. However, such SMT type electrical connectors do not effectively resolve the retention problems between the circuit board and the shell. For example, as shown in FIG. 1, a grounding pad (70) integrally formed on a shell of an electrical connector (not shown) for being grounded to a circuit board (50) is shaped into a vertically bent plate with respect to the shell. The grounding pad (70) is horizontally located above a liquid layer which is consists of a soldering paste (90) and is pre-coated on a surface of the circuit board (50) for aiding the grounding pad (70) being soldered onto the circuit board (50). Due to the liquidity of the soldering paste (90), the limited contact area between the grounding pad (70) and the soldering paste (90) will not maintain adequate retention between the grounding pad (70) and the circuit board (50). Therefore, such a shell may become separated from the circuit board. Such a SMT type electrical connectors can refer to the disclosure of Taiwan Application No. 82,111,200.
Accordingly, to resolve the above disadvantages, an object of the present invention is to provide an electrical connector which includes an improved shell means to enhance the retention between the shell means and an insulative housing of the connector.
Another object of the present invention is to provide an electrical connector which includes an improved shell means with a grounding portion to enhance the retentive effect between the shell means and the circuit board and to provide a grounding capability.